A user can interact with an environment displayed by a computer to perform functions and tasks on the computer, such as playing a game, experiencing a simulation or virtual reality environment, using a computer aided design system, operating a graphical user interface (GUI), navigate web pages, etc. Common human-computer interface devices used for such interaction include a mouse, joystick, trackball, gamepad, remote control, steering wheel, stylus, tablet, pressure-sensitive sphere, or the like, that is in communication with the computer system controlling the computer environment. The computer updates the environment in response to the user's manipulation of a physical manipulandum such as a joystick handle, button, or mouse, and provides visual and audio feedback to the user utilizing the display screen and audio speakers. The computer senses the user's manipulation of the user object through sensors provided on the interface device that send locative signals to the computer.
In some interface devices, kinesthetic force feedback and/or tactile feedback is also provided to the user, more generally known collectively herein as “haptic feedback.” These types of interface devices can provide physical sensations which are felt by the user manipulating a user manipulandum of the interface device. One or more motors or other actuators are coupled to the manipulandum and are connected to the controlling computer system. The computer system controls forces on the manipulandum in conjunction and coordinated with computer events and interactions by sending control signals or commands to the actuators. The computer system can thus convey physical force sensations to the user in conjunction with other supplied feedback as the user is grasping or contacting the interface device or manipulatable object of the interface device.
The audio feedback provided to the user is an inherent part of many application programs, especially games. Some existing haptic feedback devices are designed to provide haptic sensations based directly on the sound output from the computer. The sound output waveform is directly routed to the interface device so that tactile sensations, such as vibrations, are based directly on the sound output waveform or a filtered portion thereof, much like the way a speaker operates.
A disadvantage of existing haptic sensations based on direct sound waveforms is that the haptic sensations are simple effects based directly on the sound signals. No evaluation or processing of the sound signals is accomplished before sending the signals to the haptic device. This can cause undesirable or disconcerting haptic sensations to be output to the user since not all of the sound output is appropriate for directly translation into haptic sensations.